This invention relates to an electronic musical instrument provided with reverberation tone generating apparatus.
In the prior art electronic musical instrument provided with reverberation tone generating apparatus, the reverberation are formed by utilizing mechanical vibration of a spring or such analog delay element as a BBD (bucket brigade device) and a CCD (charge coupled device).
The reverberation characteristics of an optimum reverberation to be added to a performed musical tone are to be changed depending upon a selected tone color, so that in order to add a reverberation most suitable for the tone color of a performed musical tone, it is necessary to set such characteristics as the length and depth of the reverberation according to the selected tone color but such expedient is troublesome.
Furthermore, in an electronic musical instrument having a plurality of keyboards, for example a upper keyboard, a lower keyboard, a pedal keyboard and a solo keyboard for producing musical tones having different tone colors, it is also desirable to add reverberation tones to the musical tones produced by respective keyboards. In such a case, depending upon the mode of selection of the tone colors of respective keyboards, there occurs a case wherein a tone color suitable to be added with a reverberation tone and a tone color not suitable to be added with a reverberation tone are simultaneously selected. For example, where the tone color of a vibraphone is selected by a upper keyboard or a solo keyboard and the tone color of an organ is selected by a lower keyboard, since the amplitude envelope of the tone color of the vibraphone is long and more over since it is amplitude modulated it is not necessary to add a reverberation. However, when added with a long and deep reverberation like a performed musical tone in a church, the musical tone of the organ manifests an excellent effect. There are many cases in which a performed musical tone of a keyboard having a given tone color is produced as it is without adding thereto any reverberation tones for the purpose of producing an effect of emphasizing the given tone color.
In an electronic musical instrument having a plurality of keyboards, where it is desired to add reverberations to musical tones performed by some of the keyboards, it is desirable to construct the circuit such that a keyboard, the musical tone produced thereby being required to be added with a reverberation tone can be selected freely depending upon the selected tone color or conditions of performance of the keyboard.
Where reverberation tones are to be added to musical tone signals produced by a musical tone signal generating circuit of an electronic musical instrument provided with a plurality of keyboards, for example, an upper keyboard, a lower keyboard, a pedal keyboard and a solo keyboard, since the musical tone elements, the tone color for example, are different for different keyboards, it is desirable to make different such characteristics as the length and depth of the reverberations depending upon respective musical tone elements for the purpose of improving the performance effects. Accordingly, it is desired to make different the reverberation characteristics for different keyboards.